Infusion pump cassette and infusion pump

ABSTRACT

The present invention is related to an infusion pump cassette to deliver fluids with a tube and the like, and obtains a configuration for switching between a free flow state and a lock state in a simple manner by using components which are originally required for liquid infusion. There are provided a ring  13  that is installed in a position between the ring  13  and an inner wall surface  121  across a tube  20  in an inner space  120  and is movable in a radius direction extending radially from an axis; and an eccentric pin  15  that is movable to an infusion position (A) and a release position (B) which are different in a direction of the axis, that has an eccentric shape in which, when being at the infusion position (A), the eccentric pin  15  presses the ring  13  from an inside of a ring thereof in a direction of the radius direction so as to press the tube  20  against the inner wall surface  121  by the ring  13  to squeeze the tube  20,  and when being at the release position (B), the eccentric pin  15  releases the ring  13  from the pressing so as to release the tube  20  from the squeezing, and that, when being at the infusion position (A), receives a rotation drive force from a motor to rotate about the axis so as to send a fluid in the tube  20  out via the ring  13.

TECHNICAL FIELD

The present invention is related to an infusion pump cassette which delivers fluids with a tube and an infusion pump using a cassette, specifically, an infusion pump of rotary type.

BACKGROUND ART

Techniques to deliver fluids with tubes by using infusion pumps of rotary type are used in various fields. The infusion pump of rotary type is preferably used also, for example, when water or a nutriment is directly infused with a tube to a stomach of a gastrostomy patient.

The infusion pump of rotary type has a configuration in which a portion of a tube is squeezed and a position of the squeezing is moved in an infusion direction so as to send a fluid in the tube out.

In the infusion pump of rotary type, there are a type in which a tube is directly set to a pump and a type in which a cassette to which a tube is set and a pump main body are divided. Since the type in which a tube is directly set to a pump is only by itself in a free flow state in which a fluid flows out in free fall, it is common that a stopper to stop the fluid is separately attached at some midpoint of the tube. In addition, the type in which a cassette and a pump main body are divided includes in general a type which is in a lock state to stop flowing of the fluid before the cassette is attached to the pump main body, and is not possible to send the fluid unless the cassette is attached to the pump main body and a pump is operated and a type which is inversely in a free flow state before being attached to the pump main body.

In order to send a fluid to a stomach of a gastrostomy patient, in an unused state in which a tube remains just being attached to an infusion bag, a lock state is required so that the fluid does not flow out, and in beginning of use, it is required to send the fluid up to an end of the tube so as to remove air in the tube before sending the fluid to the stomach of the patient. In order to send the fluid up to the end of the tube, it is preferable to cause the tube to be in a free flow state and allow the fluid to fall freely. In addition, when the fluid reaches the end of the tube, it is required to attach a cassette to a pump after stopping flowing of the fluid once by returning the tube to the lock state. For these reasons, it is preferable to make a configuration in which a tube is switchable between the free flow state and the lock state. There are many types in which this switching is performed by clips and the like which are separate from infusion pumps.

In contrast, there have been proposed techniques to switch between the free flow state and the lock state by an infusion pump by itself.

In Patent Literature 1, for example, there is proposed a tube cassette for infusion pump in which a cassette main body is in a lock state when being only alone by itself, and a free flow key is fitted in a cassette main body so that the tube cassette becomes the free flow state.

In addition, in Patent Literature 2, there is proposed an infusion pump cassette which includes in a cassette a key member for switching to a free flow state by a sliding operation.

In the case of the tube cassette for infusion pump disclosed in Patent Literature 1, the free flow key which is separated from the cassette main body is required, and in addition, it is required to attach the cassette to the pump main body after removing the free flow key, and so on, and thus, it is almost equivalent to using a clip.

In addition, in the case of the infusion pump cassette disclosed in Patent Literature 2, the key member which is only required to switch between the free flow state and the lock state and is not originally required for liquid infusion is incorporated in the cassette, and so to speak, it has a configuration in which a clip is provided in a cassette.

Here, in infusion pumps of rotary type which are used in this field, silicon tubes are used almost without exception. Reasons for this may be that the silicon tube has the flexibility and may be squeezed by a small force, and when released from being squeezed, the silicon tube readily returns to a shape as before, that it is possible to produce a tube whose size such as wall thickness and whose physical characteristics such hardness are stable, and so on. However, there is a problem that the silicon tube is costly. Usually, a tube which has used once in such kind of infusion pump is discarded, and every time an infusion pump is used, a new tube is used. Accordingly, the silicon tube results in significantly increasing the running cost of such infusion pump.

As a low-cost tube, there are tubes made of polyvinyl chloride (hereinafter, referred to as PVC tube), and however, the PVC tube is inferior in flexibility, compared to the silicon tube, and in addition, the deviation of thickness and the like of the tube are large. For these reasons, when it is intended to configure an infusion pump by using a PVC tube, a large-sized motor of large drive force is required, compared to a case of using a silicon tube, and thus, resulting in being against requirements of size reduction and weight reduction.

For these reasons, it is performed to connect tubes with each other at an inlet and an outlet of an infusion pump (see Patent Literature 3). In a case of an infusion pump of this configuration, it is possible to use a silicon tube only in the infusion pump, and to use a PVC tube outside the infusion pump.

In addition, there is proposed a configuration in which, in order to infuse a liquid by a drive force an small as possible, a small rotating member is supported near an outer circumference of a rotor rotationally driven by a motor such that the rotating member may rotate freely, and a tube is pressed against a supporting surface by the rotating member (see, Patent Literatures 4 to 7).

Further, there is proposed to arrange projections at plural positions in a circumferential direction of a support surface which supports a tube pressed by a rotor driven by a motor (see Patent Literature 8).

According to the idea of the above-described Patent Literature 3, since it is possible to use a silicon tube only in an infusion pump and to use a PVC tube outside the infusion pump, it is advantageous in cost. However, the silicon tube and the PVC tube may not be simply connected with other, and it is required to couple them with each other by interposing, for example, a hard relay pipe and the like. However, when a relay pipe is used, the relay pipe is also to be discarded each time, and in addition, an operation to couple the silicon tube and the PVC tube by interposing the relay pipe therebetween, and as a result, decreasing the running cost when including the labor of the operation is limited.

In addition, the infusion pumps discussed in the above-described Patent Literatures 4 to 7 in each of which the rotor and the rotating member are combined may infuse fluid by squeezing the tube with a small drive force to deliver a liquid, compared to a configuration in which a tube is directly squeezed by a rotor without a rotating member, and however, it is difficult to obtain size reduction and weight reduction to a same extent as that of an infusion pump using a silicon tube, when considering using a PVC tube.

In addition, the proposal discussed in the above-described Patent Literature 8 in which the projections are arranged in the plural positions in the circumferential direction of the support surface is an idea in which when the operation of the infusion pump is stopped the tube is strongly pinched with the projections and a rotor so as to prevent the fluid from falling down freely through the inside of the tube. The rotor of the infusion pump described in Patent Literature 6 infuses fluid while constantly pressing the tube against the support surface even at a position other than the projections, and the presence of the projections makes an effect to increase the resistance of fluid infusion. For these reasons, the presence of the projections rather makes a negative effect in terms of drive force for fluid infusion, and thus, not only in a case in which a PVC tube is used, but also even in a case in which a silicon tube is used, a large drive force is rather required.

PRIOR ART LITERATURES Patent Literatures

Patent Literature 1: Japanese Registered Utility Model No. 3133453

Patent Literature 2: Japanese Laid-open Patent Publication No. 2001-218841

Patent Literature 3: Japanese Laid-open Patent Publication No. 2007-198150

Patent Literature 4: Japanese Laid-open Patent Publication No. H2-19672

Patent Literature 5: Japanese Laid-open Patent Publication No. H2-238188

Patent Literature 6: Japanese Laid-open Patent Publication No. H4-303189

Patent Literature 7: Japanese Laid-open Patent Publication No. 2005-61329

Patent Literature 8: Japanese Laid-open Patent Publication No. 2010-138742

ABSTRACT OF THE INVENTION Technical Problem

In view of the foregoing, it is an object of the present invention to provide an infusion pump cassette and an infusion pump which obtain simple structures through switching the free flow state and the lock state by using components which are originally required for liquid infusion.

Solution to Problem

An infusion pump cassette to obtain the above-described object includes:

a main body member that is defined by an inner wall surface which encircles an axis to spread, and that forms an inner space which receives a tube extending from an outside to arrange the tube along the inner wall surface and causes the tube to extend to the outside;

a ring-shaped member that is installed in a position between the ring-shaped member and the inner wall surface across the tube in the inner space, and that is movable in a radius direction extending radially from the axis; and

-   -   an eccentric member that is movable to an infusion position and         a release position which are different in a direction of the         axis, that has an eccentric shape in which, when being at the         infusion position, the eccentric member presses the ring-shaped         member from an inside of a ring thereof in a direction of the         radius direction so as to press the tube against the inner wall         surface by the ring-shaped member to squeeze the tube, and when         being at the release position, the eccentric member loosens the         pressing for the ring-shaped member or releases the ring-shaped         member from the pressing so as to loosen the squeezing for the         tube or release the tube from the squeezing, and that, when         being at the infusion position, receives a rotation drive force         from a motor to rotate about the axis so as to send a fluid in         the tube out via the ring-shaped member.

The infusion pump cassette according to the present invention has a configuration in which the eccentric member receives a rotation drive force from the motor to rotate while pressing the ring-shaped member so as to send the fluid in the tube out, and accordingly, the eccentric member is an essential member for fluid infusion. The infusion pump cassette according to the present invention makes it possible for the eccentric member which is an essential member for fluid infusion to move to the infusion position and to the release position. With this, it is obtained to switch between the lock state and the free flow state with a simple configuration.

Here, in the infusion pump cassette according to the present invention, it is preferable that the infusion pump cassette further includes a fixing mechanism that fixes the eccentric member at the infusion position in a releasable manner

When this fixing mechanism is arranged, it is possible to securely hold the tube in the lock state.

As the fixing mechanism, it is preferable that the fixing mechanism includes a lock section that fixes the eccentric member being at the infusion position at the infusion position, and that, when a force of a predetermined value or more in a direction toward the release position is applied, releases the fixing so as to allow the eccentric member to go toward the release position.

In this case, it is possible to obtain the free flow state only by an operation of pressing with applying a force, and thus the operability is improved.

Or, as the fixing mechanism, it is also a preferable configuration that the fixing mechanism includes a lock member that is movable between a lock position in which the lock member locks to the eccentric member being at the infusion position to cause the eccentric member to be immovable from the infusion position and a retraction position in which the lock member retracts from the lock position to makes it possible for the eccentric member to move to the release position. This lock member may be used jointly as the above-described lock section, or the lock member may only be arranged without a lock section being arranged.

When the lock member is arranged, it is possible to more securely make fixing in the lock state.

In addition, in the infusion pump cassette according to the present invention, it is preferable that the inner wall surface of the main body member is an inner wall surface including an uneven surface in which plural ridgelines being arranged in a direction encircling the axis and in a same distance from the axis and plural depressed sections being depressed in directions more away from the axis than the ridgelines are alternately arranged.

An infusion pump cassette of this mode is a cassette having a configuration in which there are provided on the inner wall surface the uneven surface in which the ridgelines and the depressed sections are alternately arranged, the tube is pressed against the ridgelines of the uneven surface to be squeezed, and the squeeze position is moved from a ridgeline to a ridgeline to infuse the liquid. When this configuration is applied, since the force at the time of squeezing is concentrated to the ridgelines, it is possible to sufficiently squeeze a PVC tube by a same level of drive force as that of a drive force used in an infusion pump using, for example, a conventional silicon tube. In other words, according to the infusion pump cassette of this mode, without sacrificing size reduction and weight reduction, it is possible to make cost reduction with respect to an infusion pump by using a PVC tube. Or, by using a silicon tube, and also using a motor having a small size whose drive force is further smaller than that of a conventional one, it is possible to make further size reduction and weight reduction.

Further, in the above-described mode including the uneven surface, it is preferable that the above-described eccentric member causes, when being at the infusion position, the ring-shaped member to press the tube being received in the inner space against adjacent plural ridgelines of the uneven surface so as to sandwich the tube between the ring-shaped member and each of the plural ridgelines across the tube to squeeze the tube, and receives a rotation drive force from a motor to cause a ridgeline against which the tube is pressed to be sequentially taken over by a next ridgeline neighboring in the direction encircling the axis so as to send the fluid in the tube out.

When the tube is simultaneously pressed against the adjacent plural ridgelines, portions of the tube between the ridgelines may not expand much and become almost squeezed states. For these reasons, a liquid amount in an area between the ridgelines in the tube is decreased.

Accordingly, although the tube is pressed against the ridgelines, so to speak, dispersedly, an infusion efficiency of a same level as that of a configuration in which a tube is pressed continuously along a direction of the length is obtained.

In addition, in the infusion pump cassette according to the above-described present invention, it is further preferable that the main body member includes plural slits which are formed separately with spaces in the direction encircling the axis and each of which penetrates from the inner wall surface to an external wall surface.

As described above, the PVC tube has large variations in size such as its thickness and the like. When the thickness is large, combined with that the PVC tube is inferior in the flexibility, the motor is loaded with an excessive force, and thus, an operation failure may occur.

When the above-described slits are arranged, in case a situation in which the motor is loaded with an excessive load occurs, portions between two slits deforms outward, and with this, it is possible to avoid an excessive load to the motor. Accordingly, by arranging the above-described slits, further large variations of the size or physical characteristics of a tube to be used in this infusion pump cassette may be tolerated.

In addition, an infusion pump according to the present invention includes:

an infusion pump cassette according to the present invention; and

a pump main body that includes a motor therein, and receives an attachment of the infusion pump cassette to transfer a rotation drive force from the motor to the eccentric member being at the infusion position.

Advantageous Effects of Invention

According to the infusion pump cassette and the infusion pump of the present invention, switching between the lock state and the free flow state is obtained with a simple configuration by using members which are essential for fluid infusion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of an infusion pump cassette as a first embodiment of the present invention.

FIG. 2 is an external perspective view of the infusion pump cassette whose exploded perspective view is illustrated in FIG. 1 in a state of being assembled.

FIG. 3 is a sectional view along arrows X-X illustrated in part (A) of FIG. 2.

FIG. 4 is a view illustrating a state in which the infusion pump cassette whose exploded perspective view is illustrated in FIG. 1 is viewed from below, while a disk section of an eccentric member and a holding plate are removed from the infusion pump cassette.

FIG. 5 is a perspective view of the assembled infusion pump cassette viewed from a point of view different from that of FIG. 2.

FIG. 6 is a perspective view illustrating attachment sections of the infusion pump cassette and a pump main body.

FIG. 7 is a transparent view illustrating a state in which the infusion pump cassette is attached to the pump main body while seeing through the pump main body.

FIG. 8 is a side view illustrating a drive member included in the pump main body.

FIG. 9 is a perspective view illustrating the drive member included in the pump main body.

FIG. 10 is a view illustrating a first modified example of the infusion pump cassette according to the present invention.

FIG. 11 is a view illustrating a second modified example of the infusion pump cassette according to the present invention.

FIG. 12 is a view illustrating a third modified example of the infusion pump cassette according to the present invention.

FIG. 13 is a view illustrating a fourth modified example of the infusion pump cassette 103 according to the present invention.

FIG. 14 is a perspective view of a cap included in the infusion pump cassette of the fourth modified example.

FIG. 15 is an exploded perspective view of an infusion pump cassette as a second embodiment according to the present invention.

FIG. 16 is an external perspective view of the assembled infusion pump cassette when viewed from obliquely above.

FIG. 17 is an external perspective view of the assembled infusion pump cassette when viewed from obliquely below.

FIG. 18 is a bottom view of an infusion pump cassette of the second embodiment.

FIG. 19 is an enlarged view of a section of the circle R illustrated in FIG. 18.

FIG. 20 is a longitudinal sectional view in which the infusion pump cassette is sectioned to be viewed along a plane including an axis C.

FIG. 21 is a perspective view of a pump main body when viewed from above.

FIG. 22 is a perspective view illustrating both of the pump main body in a state in which an opening/closing lid is opened and the infusion pump cassette.

FIG. 23 is a view in which a casing of the pump main body is represented with two-dotted lines except for the opening/closing lid and an outline of an internal configuration thereof is illustrated.

FIG. 24 is a view illustrating behaviors when an infusion pump cassette is attached to an attachment section of the pump main body.

FIG. 25 is a view illustrating a bottom surface of the pump main body and a pump holder separately.

FIG. 26 is a view illustrating a state in which the pump main body is attached to the pump holder.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, exemplary embodiments according to the present invention will be explained.

FIG. 1 is an exploded perspective view of an infusion pump cassette as a first embodiment of the present invention. In addition, FIG. 2 is an external perspective view of the infusion pump cassette whose exploded perspective view is illustrated in FIG. 1 in a state of being assembled, FIG. 3 is a sectional view along arrows X-X illustrated in part (A) of FIG. 2, and FIG. 4 is a view illustrating a state in which the infusion pump cassette whose exploded perspective view is illustrated in FIG. 1 is viewed from below, while a disk section of an eccentric member and a holding plate are removed from the infusion pump cassette. Further, FIG. 5 is a perspective view of the assembled an infusion pump cassette viewed from a point of view different from that of FIG. 2.

In here, a tube 20 to go through an infusion pump cassette is also illustrated. The tube 20 is originally longer, and only a portion thereof near the infusion pump cassette 10 is illustrated in here.

FIG. 1 illustrates an axis C of the infusion pump cassette. This infusion pump cassette 10 includes, as illustrated in FIG. 1, a cap 11, a main body 12, a ring 13, a holding plate 14 and an eccentric pin 15. In here, the tube 20 which is to be housed in the main body 12 and is in a form when being housed in the main body 12 is illustrated.

The main body 12 has an inner space 120 defined by an inner wall surface 121 having an arc shape illustrated in FIG. 4. The inner wall surface 121 is a surface which spreads in a same distance from the axis C illustrated in FIG. 1.

As illustrated in FIG. 2, the tube 20 extends from an outside, is housed in the inner space 120 of the main body 12, is arranged to go round circumferentially along the inner wall surface 121 having the arc shape in the inner space 120, and then extends to the outside of the main body 12 again.

In addition, the main body 12 includes lock claws 122 each having a cantilever shape on both respective sides. The lock claws 122 play a role of mating with a pump main body which will be described later to lock the infusion pump cassette 10 such that the infusion pump cassette 10 is removable from the pump main body. The lock claws 122 includes operation sections 122 a, respectively, and the operation sections 122 a respectively arranged on the both side sections are operated such that they are compressed to each other in a state of being locked to the pump main body. Then, the locking of the lock claws 122 is released from the pump main body, and the infusion pump cassette 10 may be removed from the pump main body. Further, slits 123 are formed at three positions (see FIG. 4) on a circumference of a lower section of the main body 12. The slits 123 are for making it possible for the holding plate 14 to be assembled with an appropriate force and for the eccentric pin 15 to move vertically.

The eccentric pin 15 is configured to be movable to an infusion position illustrated in part (A) of FIG. 2 and part (A) of FIG. 3 and to a release position illustrated in part (B) of FIG. 2 and part (B) of FIG. 3 where the infusion position and the release position are positions different from each other with respect to a direction in which the axis C (see FIG. 1) extends. When the eccentric pin 15 is at the infusion position illustrated in part (A) of FIG. 2 and part (A) of FIG. 3, the tube 20 is squeezed by the ring 13 to become a lock state.

In addition, when the eccentric pin 15 is moved to the release position illustrated in part (B) of FIG. 2 and part (B) of FIG. 3, the tube 20 is released from the pressing by the ring 13 to become a free flow state.

In order to assemble the infusion pump cassette 10, after the tube 20 is housed in a ring form illustrated in FIG. 1 in the inner space 120 of the main body 12, the ring 13 is arranged in the ring of the tube 20. In other words, the ring 13 is installed at a position between the ring 13 and the inner wall surface 121 (see FIG. 3, FIG. 4) of the main body 12 across the tube 20 in the inner space 120. The ring 13 is movable in a radius direction extending radially from the axis C (see, FIG. 1), that is, in a plane spreading in two directions of a lateral direction illustrated in FIG. 3 and a direction perpendicular to the sheet thereof.

After the ring 13 is installed in the inner space 120 of the main body 12, the holding plate 14 having the ring shape is installed in the inner space 120 of the main body 12. A fixing groove 124 is formed to go round circumferentially on the inner wall surface 121 forming the inner space 120 of the main body 20, and the holding plate 14 is fitted in the fixing groove 124. The holding plate 14 is a member for supporting the ring 13 from below such that the ring 13 does not falls down.

Further, after the holding plate 14 is attached, the eccentric pin 15 is inserted from below. The eccentric pin 15 includes, as illustrated in FIG. 1, a head section 151, an eccentric cam section 152 and a disk section 153. An opening 125 continuing to the inner space 120 is formed in an upper section of the main body 12. The eccentric pin 15 is inserted in the inner space 120 of the main body 12 from below, and becomes a state in which the head section 151 of the eccentric pin 15 protrudes from the opening 125 above the main body 12. The cap 11 is firmly fitted to the head 151 in the state of protruding above the main body 12 to an extent in which the cap 11 is not removable from the head section 151 in a normal usage condition.

In addition, the eccentric cam section 152 of the eccentric pin 15 has a shape of being eccentric from the axis C, and when the eccentric pin 15 is at the infusion position, as illustrated in part (A) of FIG. 3 and FIG. 5, the eccentric pin 15 plays a role of pressing the tube 20 via the ring 13 against the inner wall surface 121 to squeeze the tube 20 by pressing the ring 13 from an inside thereof in a direction of a radius direction (a lateral direction in part (A) of FIG. 3).

The eccentric pin 15 is a member which receives a rotation drive force from the pump main body to rotate about the axis C as a rotation center, and when the eccentric pin 15 being at the infusion position rotates, a position at which the tube 20 is squeezed by the ring 13 continuously changes in a direction of an arrow A illustrated in FIG. 4, and thus, a fluid in the tube 20 is sent out.

In addition, a lock groove 126 is provided circumferentially on a lower section of the inner wall surface 121 forming the inner space 120 of the main body 12. When the eccentric pin 15 is at the infusion position illustrated in part (A) of FIG. 2 and part (A) of FIG. 3, a state in which a circumference edge section 153 a of the disk section 153 of the eccentric pin 15 enters the lock groove 126 to be locked occurs. The locking may be released by pressing the cap 11 from above. The eccentric pin 15 receives, in this state, a rotation drive from the pump main body to rotate, and sends the fluid in the tube 10 out via the ring 13. The lock groove 126 also plays a role as a rotation bearing for the rotation of the eccentric pin 15.

In the state in which the circumference edge section 153 a of the disk section 153 enters the lock groove 126, the cap 11 is in a state of being pushed up up to a position which is away upward from the main body 12 illustrated in part (A) of FIG. 2 and part (A) of FIG. 3 by the head section 151 of the eccentric pin 15.

The above-described slits 123 are formed in the main body 12, and when the cap 11 is pressed down from above with an appropriate force of a predetermined value or more, the fixing by that the disk section 153 enters the lock groove 126 is released, and the disk section 153 goes down up to the release position illustrated in part (B) of FIG. 2 and part (B) of FIG. 3. At this moment, the cap 11 goes down up to a position immediately above the main body 12. When the eccentric pin 15 moves to the release position, the eccentric cam section 152 of the eccentric pin 15 comes out of the ring 13 as illustrated in part (B) of FIG. 3, and the tube 20 is released from being squeezed to become the free flow state by an elastic force of the tube 20 itself. Incidentally, in the present embodiment, the eccentric pin 15 being at the release position almost completely releases the ring 13 from the pressing, and however, it is acceptable as far as the tube 20 may sufficiently become the free flow state, and when there are restrictions on layout, the eccentric pin 15 may, also at the release position, remain pressing the ring 13 to an extent in which the free flow state is secured.

In other words, the eccentric pin 15 has an eccentric shape to loosen the squeezing for the tube 20 or release the tube 20 from being squeezed by loosening the pressing for the ring 13 or releasing the ring 13 form the pressing when the eccentric pin 15 is at the release position.

Further, as illustrated in FIG. 5, openings 154 which are arranged in plural at equal intervals in a circumferential direction in order to receive the rotation drive force from the pump main body are formed on a bottom surface 153 b of the disk section 153 of the eccentric pin 15. Relationships with the pump main body will be describe later.

In the infusion pump cassette 10 before use, the eccentric pin 15 is at the infusion position illustrated in part (A) of FIG. 2 and part (A) of FIG. 3, and the tube 20 is in the lock state in which the fluid does not flow. An infusion bag containing the fluid is attached to an upper end of the tube 20 which extends long, and the cap 11 is pressed to cause the eccentric pin 15 to move to the release position illustrated in part (B) of FIG. 2 and part (B) of FIG. 3. Then, the tube 20 becomes the free flow state, and the fluid in the infusion bag flows down in a free fall manner in the tube 20. At a timing when the fluid reaches a lower end of the tube 20, then the cap 11 is lifted up to cause the eccentric pin 15 to again move to the infusion position illustrated in part (A) of FIG. 2 and part (A) of FIG. 3. Thus, the tube again becomes the lock state, and the liquid flowing stops. In this state, the infusion pump cassette 10 is attached to the pump main body. Then, receiving a rotation drive force from the pump main body, the eccentric pin 15 rotates, a squeezing position for the tube 20 by the ring 13 rotates in the direction of arrow A illustrated in FIG. 4, and the fluid in the tube 20 is sent out. As described above, the fluid in the infusion bag is infused by a flow amount according to a rotation speed of the infusion pump.

FIG. 6 is a perspective view illustrating attachment sections of the infusion pump cassette and a pump main body. In addition, FIG. 7 is a transparent view illustrating a state in which the infusion pump cassette is attached to the pump main body while seeing through the pump main body. Further, FIG. 8 and FIG. 9 are a side view and a perspective view, respectively, illustrating a drive member included in the pump main body.

A pump main body 30 illustrated in here is an example of the pump main body of the infusion pump according to the present invention.

The pump main body 30 includes, as illustrated in FIG. 7, a casing 31, a motor 32 which is housed in the casing 31, and a drive member 33 which transfers a rotation drive force of the motor 32 to the infusion pump cassette 10.

An attachment section 311 to receive an attachment of the infusion pump cassette 10 is formed in the casing 31 of the pump main body 30. In the attachment section 311, a depressed section 312 having a shape to agree with a shape of a lower end section of the infusion pump cassette 10 is formed, and two openings 313 which the two lock claws 122 provided in the main body 12 of the infusion pump cassette 10 enter are formed. Further, an opening 314 through which an upper end of a drive shaft 33 is seen is formed in a center of the attachment section 311. The infusion pump cassette 10 is attached to the attachment section 311 of the pump main body 30 with a bottom surface illustrated as oriented upward in FIG. 6 being oriented downward. Then, the two lock claws 122 which are arranged on the both side sections each on the left and the right enter the two openings 313, respectively, as illustrated in FIG. 7, and the infusion pump cassette 10 is fixed to the pump main body 30 so as not to be separated from the pump main body 30. The operation sections 122 a to be pressed by fingers are provided in the lock claws 122. When the two operation section 122 a of the lock claws are pressed such that a distance between them is decreased, the locking of the lock claws 122 to the pump main body 30 is released, and then just being lifted, the infusion pump cassette 10 is removed from the pump main body 30.

The drive member 33 provided in the pump main body 30 includes, as illustrated in FIG. 8 and FIG. 9, a fixing plate 331, a gear 332, a drive shaft 333, a head 334 and a coil spring 335.

The fixing pate 331 is fixed to the casing 31 not to be movable with respect to the casing 31. The gear 332 is a gear which is fixed to the drive shaft 333 and receives a rotation drive force from the motor 32 (see FIG. 7) to transfer the force to the drive shaft 333. When the rotation drive force is transferred from the motor 32 to the gear 332, the drive shaft 333 rotates together with the gear 332. The head 334 is provided in an upper end section of the drive shaft 333 between the head 334 and the fixing plate 331 across the coil spring 335. The fixing plate 331 is fixed to the casing 31. An opening 334 a through which the drive shaft 333 goes is formed in the head 334, as illustrated in FIG. 9, and further, two long openings 334 b which continue to the opening 334 a and extend in the radius direction are formed. Driving pins (not illustrated in the drawings) which protrude from the drive shaft 333 in the radius direction are fixed to the upper end section of the drive shaft 333, and the driving pins enter the two long openings 334 b. For these reasons, the head 334 is movable in a vertical direction with respect to the drive shaft 333, and rotates integrally with the drive shaft 333 with respect to the rotation of the driving shaft 333.

In addition, plural projections 334 s which respectively enter the plural openings 154 provided in the bottom surface 153 b (see FIG. 5, FIG. 6) of the eccentric pin 15 of the infusion pump cassette 10 are provided on an upper surface of the head 334. When the drive shaft 333 rotates in the state in which the projections 334 c on the upper surface of the head 334 enter the openings 154 on the bottom surface 153 b of the eccentric pin 15 of the infusion pump cassette 10 in the state of being attached to the attachment section 311 of the pump main body 30, the head 334 also rotates together with the drive shaft 333, the rotation of the head 334 is transferred to the eccentric pin 15 of the infusion pump cassettes 10 and the eccentric pin 15 rotates, and thus, the fluid in the tube 20 is infused based on the above-described principle.

Here, in the beginning after the infusion pump cassette 10 is attached to the pump main body 30, there is a case in which the projections 334 c on the upper surface of the head 334 do not enter the openings 154 on the bottom surface 153 b of the eccentric pin 15. In this case, the head 334 c abuts against the bottom surface 153 b of the eccentric pin 15, and the head 334 is pressed down against the spring force of the coil spring 335.

Part (A) of FIG. 8 and part (A) of FIG. 9 illustrate the drive member 33 in a state in which the drive member 334 is pressed down as described above.

When the motor 32 illustrated in FIG. 7 is rotated while the head 334 remains in the state of part (A) of FIG. 8 and part (A) of FIG. 9, the drive shaft 333 and the head 334 start to rotate via the gear 332, and at a timing when positions of the openings 154 on the bottom surface 153 b of the eccentric pin 15 and positions of the projections 324 c on the upper surface of the head 334 coincide, the head 334 is pressed by the coil spring 335 to be lifted and the projections 334 c enter the openings 154.

Part (B) of FIG. 8 and part (B) of FIG. 9 illustrate the drive member 33 in the state in which the projections 334 c enter the openings 154.

After the projections 334 c enter the openings 154, the eccentric pin 15 rotates integrally with the rotation of the drive shaft 333 and the head 334.

This ends the explanations of the one embodiment according to the present invention, and in the following, various kinds of modified examples will explained. Incidentally, in the respective drawings referred in the following explanations, constitutional elements corresponding to the constitutional elements of the above-described embodiment are denoted by signs same as those denoted in the respective drawings described above, and differences from the above-described embodiment will only be explained.

FIG. 10 is a view illustrating a first modified example of the infusion pump cassette according to the present invention.

Instead of the lock groove 126 illustrated in FIG. 3, a flange 127 which circumferentially projects inward is formed in a lower section of an inner wall surface 121 of a main body 11 of an infusion pump cassette 101 according to the first modified example illustrated in FIG. 10. Due to the forming of the flange 127, a shape of a circumference edge of a disk section 153 of an eccentric pin 15 is also changed, compared to the embodiment illustrated in FIG. 3. The flange 127 plays a role same as that of the lock groove 126 illustrated in FIG. 3. In other words, the flange 127 is for fixing the eccentric pin 15 at the infusion position illustrated in this FIG. 10. When a cap 11 is pressed from above with a force of a predetermined value or more, the locking is released, and the eccentric pin 15 moves to the release position (see part (B) of FIG. 3).

As described above, a configuration in which the flange 127 illustrated in this FIG. 10 is formed instead of the lock groove 126 illustrated in FIG. 3 is acceptable.

FIG. 11 includes a sectional view (part (A)) and a perspective view (part (B)) illustrating a second modified example of an infusion pump cassette according to the present invention.

Neither the lock groove 126 illustrated in FIG. 3 nor the flange 127 illustrated in FIG. 11 is formed in an infusion pump cassette 102 of the second modified example illustrated in FIG. 11.

In the infusion pump cassette 102 of the second modified example illustrated in this FIG. 11, a groove 128 is formed on an upper surface of a main body 12, and a stopper 16 to be operated to slide along the groove 128 is provided in the groove 128. A depressed section 161 having an arc shape is formed on a side of the eccentric pin 15 of the stopper 16.

In addition, the eccentric pin 15 of the infusion pump cassette 102 according to the second modified example includes a groove 154 which is formed circumferentially to receive the depressed section 161 of the stopper 16 at a height position same as that of the stopper 16 when the eccentric pin 15 is at the infusion position illustrated in this FIG. 11.

In the case of the infusion pump cassette 102 according to the second modified example, the stopper 16 is slid to move to a lock position in which the depressed section 161 thereof enters the groove 154, so that the eccentric pin 15 is fixed at the infusion position. In order to move the eccentric pin 15 from the infusion position to the release position, after the stopper 16 is slid in a direction in which the depressed section 161 goes away from the groove 154 and is moved to a retraction position in which the locking between the depressed section 16 and the groove 154 is released, the cap 11 is pressed down. With this, the eccentric pin 15 moves to the release position.

In the case of the infusion pump cassette 102 according to the second modified example, since even if the cap 11 is pressed carelessly the cap 11 remains at the infusion position as far as the stopper 16 is being inserted in the groove 154 of the eccentric pin 15, possibilities that the fluid in the tube 20 inadvertently leaks out are further securely avoided.

Incidentally, in the infusion pump cassette 102 of the second modified example illustrated in FIG. 11, a configuration in which, in addition to the stopper 16 illustrated in FIG. 11, a locking mechanism similar to the lock groove 126 illustrated in FIG. 3 or the flange 127 illustrated in FIG. 10 is further provided is acceptable.

FIG. 12 is a view illustrating a third modified example of the infusion pump cassette according to the present invention.

In an infusion pump cassette 103 of the third modified example illustrated in FIG. 12, a groove 153 c is formed to go round circumferentially on a circumference edge of a disk section 153 of an eccentric pin 15. In addition, a projection 129 which enters the groove 153 c is formed in an inner wall surface 121 forming an inner space 120 of a main body 120.

Further, the infusion pump cassette 103 of the third modified example includes a stopper 17 to be operated to slide between a lock position in which the stopper 17 enters the groove 153 c and a retraction position in which the stopper 17 is removed from the groove 153 c. In addition, due to the provision of the stopper 17, the main body 12 is also changed to a configuration to support the stopper 17.

The infusion pump cassette 103 of the third example has, similarly to the above-described embodiment, a configuration in which a lower section of the main body 12 easily deforms by slits 123 (see FIG. 3, etc.) provided in a lower section of the main body 12. For these reasons, when the cap 11 is pressed down when the stopper 17 is in a state of being out of the groove 153 c as illustrated in FIG. 12, a lower end section of the main body 12 elastically deforms and the locking between the groove 153 c and the projection 129 is released, the eccentric pin 15 moves from the infusion position illustrated in FIG. 12 to the release position (see part (B) of FIG. 3). However, a portion supporting the stopper 17 of the main body 12 has a strength of an extent of being hardly deformed elastically by a force of a same level as an operation of pressing down the cap, and, when the stopper 17 is slid to enter the groove 153 c, even in a case in which the cap 11 is pressed unintentionally, the eccentric pin 15 remains at the infusion position illustrated in this FIG. 12.

As described above, also in the case of the infusion pump cassette 103 of the third modified example, similarly to the infusion pump cassette 102 of the second modified example illustrated in FIG. 11, it is further securely prevented that the fluid in the tube 20 unintentionally leaks out.

Incidentally, in the infusion pump cassette of the third modified example, instead of the projection 129 of the main body 12, or in addition to providing the projection 129, a flange similar to the flange 127 of the infusion pump cassette 101 of the first modified example illustrated in FIG. 10 may be provided.

FIG. 13 is a view illustrating a fourth modified example of the infusion pump cassette 103 according to the present invention. In addition, FIG. 14 is a perspective view of a cap included in the infusion pump cassette of the fourth modified example.

As illustrated in FIG. 14, an opening 111 which goes through vertically in a center thereof and a slit 112 which continues to the opening 111 in the center are formed in a cap 11 which is included in an infusion pump cassette 104 of the fourth modified example. The cap 11 has a configuration in which when a force of a certain extent is applied, the slit 112 opens elastically to expand the opening 111 in the center.

In addition, a head section 151 of an eccentric pin 15 of the infusion pump cassette 104 according to the fourth modified example is formed in a spherical shape as illustrated in FIG. 13, and a depressed section 111 a having a spherical shape to agree with the shape of the head section 151 having the spherical shape is formed in the opening 111 of the cap 11.

Part (A) of FIG. 13 illustrates the infusion pump cassette when the eccentric pin 15 is at the infusion position.

In here, an upper end edge of the opening 111 of the cap 11 supports the head section 151 having the spherical shape of the eccentric pin 15, and a lower end of the cap 11 simultaneously abuts against an upper surface of the main body 12. As described above, the eccentric pin 15 is locked at the infusion position.

In order to move the eccentric pin 15 being at the infusion position to the release position, the cap 11 is lifted upward at first. When the cap 11 is lifted by a force of a predetermined value or more, the cap 11 is lifted while the slit 112 formed in the cap 11 is opening, and, as illustrated in part (B) of FIG. 13, the head section 151 having the spherical shape of the eccentric pin 15 fits in the depressed section 111 a of the opening 111 of the cap 11.

Afterwards, when the cap 11 is pressed down together with the eccentric pin 15, as illustrated in FIG. 13 (part (C)), the eccentric pin 15 goes down together with the cap 11, and the eccentric pin 15 moves to the release position.

In order to move the eccentric pin 15 being at the release position to the infusion position, the cap 11 being in the state illustrated in part (C) of FIG. 13 is lifted up to a state illustrated in part (B) of FIG. 13. Then, this time, only the cap 11 is pressed down while the eccentric pin 15 is being held from below. With this, the cap 11 and the eccentric pin 15 become the state illustrated in part (A) of FIG. 13, and the eccentric pin 15 moves to the infusion position to become the state of being locked.

In the case of the infusion pump cassette 104 of the fourth modified example illustrated in this FIG. 13, when the eccentric pin 15 is at the infusion position, the state in which the head section 151 protrudes above the cap 11 occurs, and when the eccentric pin 15 moves to the release position, the state in which the head section 151 retracts in the opening 111 of the cap 11 occurs. In the cases of the embodiment and the first to the third modified examples which have explained above, whether the eccentric pin 15 is at the infusion position or at the release position is visually confirmed based on a position in the vertical direction of the cap 11, and in the case of the fourth modified example illustrated in FIG. 13, whether the eccentric pin 15 is at the infusion position or at the release position is visually confirmed more clearly by the protrusion and the retraction of the head 151, and thus, it is further effective to prevent an error.

Next, an infusion pump cassette of a second embodiment according to the present invention will be describe. A mechanism to move an eccentric pin 55 (see FIG. 15; corresponding to the eccentric pin 15 in the infusion pump cassette of the first embodiment illustrated in FIG. 1) to the infusion position and to the release position and a fixing configuration are similar to the moving mechanism and the fixing configuration in the infusion pump cassette according to the first embodiment, and explanations of the moving mechanism and the fixing configuration in the infusion pump cassette of the second embodiment in the following will be omitted.

FIG. 15 is an exploded perspective view of an infusion pump cassette as the second embodiment according to the present invention.

In addition, FIG. 16 and FIG. 17 include external perspective views of the assembled infusion pump cassette, viewed from obliquely above and obliquely below, respectively.

In here, a tube 20 which goes through the infusion pump cassette is also illustrated. The tube 20 has originally a longer length, and in here, only a portion thereof near an infusion pump cassette 50 is illustrated.

FIG. 15 illustrates an axis C of the infusion pump cassette 50. As illustrated in FIG. 15, the infusion pump cassette 50 includes a cap 51, a main body 52, a ring 53, a holding plate 54 and an eccentric pin 55. In here, the tube 20 which is to be housed in the main body 52 and is in a form when being housed in the main body 52 is illustrated.

The main body 52 corresponds to an example of the main body member according to the present invention. In addition, the ring 53 corresponds to an example of the ring-shaped member according to the present invention, and the eccentric pin corresponds to an example of the eccentric pin according to the present invention.

The main body 52 has an inner space 520 which is defined by an inner wall surface formed in an arc shape as a whole, including an uneven surface 521 appeared in FIG. 17. The uneven surface 521 is a surface which spreads in a same distance from an axis C illustrated in FIG. 15, and spreads in an arc shape as a whole where a ridgelines 521 a each extending in a ridge shape in a vertical direction and depressed sections 521 b each being depressed in an arc shape alternately repeat. The tube 20 extends from an outside of the infusion pump cassette 50 and goes through a tube passing port 522 to be housed in the inner space 520 of the main body, and is arranged to go round circumferentially along the uneven surface 521 in the inner space 520, and again extends from the tube passing port 522 to the outside of the main body 52.

In addition, the main body 52 includes arms 524 which protrude on both sides of an outer circumference surface 523, respectively. These arms 524 are for preventing rotation when the infusion pump cassette 50 is attached to a pump main body which will be described later and receives a rotation drive force from a motor.

In addition, slits 525 which are formed in plural with spaces in a direction encircling the axis C are formed in the main body 52. Each of these slits 525 goes through from an inner wall surface defining the inner space 520 through the outer circumference surface 523. With these slits 52 provided, when the inner wall surface is pressed, it is elastically expands outward in an appropriate degree. With this, the pressed force is mitigated.

In addition, an opening 526 through which a head section 551 of the eccentric pin 55 which will be described later is allowed to go is formed in an upper section in the main body 52. In addition, as illustrated in FIG. 17, a large opening having a diameter approximately same as that of the inner space 520 is formed in a lower section of the main body.

In order to assemble the infusion pump cassette 50, after the tube 20 is housed in a ring form illustrated in FIG. 15 in the inner space 520 of the main body 52, the ring 53 is arranged in the ring of the tube 20. In other words, the ring 53 is installed in a position between the ring 53 and the uneven surface 521 (see FIG. 17) of the inner space 520 of the main body 52 across the tube 20. The ring 53 is movable in a radius direction extending radially from the axis C (see FIG. 1), in other words, in a plane having the axis C as its perpendicular line.

After the ring 53 is installed in the inner space 520 of the main body 52, the holding plate 54 having the ring shape is installed in the inner space 520 of the main body 52. A fixing groove 527 (see part (A) of FIG. 20) is formed to go round circumferentially on an inner circumference surface defining the inner space 520 of the main body 52, and since the slits 525 are formed in the main body 52, the holding plate 54 is fitted in the fixing groove 527 while expanding the main body 52 outward. The holding plate 54 is a member for supporting the ring 53 so as to prevent the ring 53 from falling down.

Further, after the holding plate 54 is attached, the eccentric pin 55 is inserted from below. The eccentric pin 55 includes, as illustrated in FIG. 15, a head section 551, an eccentric cam section 552 and a disk section 553. The eccentric pin 55 is inserted in the inner spade 520 of the main body 52 from below, and becomes a state in which the head section 551 of the eccentric pin 55 protrudes above the main body 52 from the opening 526 formed in the upper section of the main body 52.

A guide groove 528 (see FIG. 20) in which the disk section 553 of the eccentric pin 552 is fitted to guide the rotation of the eccentric pin 552 is formed immediately under the fixing groove 527 of the main body 52. When the eccentric pin 55 is inserted up to the state in which the head section 551 of the eccentric pin 55 protrudes upward from the opening 526 of the main body 52, the disk section 553 of the eccentric pin 55 is fitted in the guide groove 528 while expanding the main body 52 outward. In addition, the cap 51 is fitted firmly in the head section 551 in the state of protruding above the main body 52 to an extent in which removing from the head section 551 is impossible in a normal usage condition. The opening 526 of the main body 52 also plays a role of guiding the rotation of the eccentric pin 55, together with the guide groove 528.

In addition, the eccentric cam section 552 of the eccentric pin 55 has a shape eccentric from the axis C, and plays a role of squeezing the tube 20 by pressing the ring 53 from an inside thereof in a direction of the radius direction so as to press the tube 20 against the ridgelines 521 a of the uneven surface 521 via the ring 53. When the eccentric pin 55 rotates about the axis C, a squeezing position sequentially changes such that a ridgeline 521 a against which the tube is pressed is caused to be sequentially taken over by a neighboring next ridgeline 521 a, and with this, the fluid in the tube 20 is sent out.

In addition, as illustrated in FIG. 17, four openings 553 a surrounding the axis C are formed on a bottom surface of the disk section 553 of the eccentric pin 55. Drive pins of a pump main body which will be described later fit in these opening 553 a, and a rotation drive force is transferred to the eccentric pin 55 by rotation of the drive pins.

FIG. 18 is a bottom view of an infusion pump cassette of the present embodiment, and FIG. 19 is an enlarged view of a section of the circle R illustrated in FIG. 18. In these FIG. 18 and FIG. 19, while the holding plate 54 and the disk section 553 of the eccentric pin 55 are made transparent, the inner space 520 of the main body 512 is illustrated.

In addition, FIG. 20 is a longitudinal sectional view in which the infusion pump cassette is sectioned to be viewed along a plane including an axis C. Part (A) and part (B) of FIG. 20 are views illustrated by sectioning with a planes each including the axis C and respectively including each of two dashed lines D1 and D2 illustrated in FIG. 18. In parts (A) and (B) of FIG. 20, the ridgelines 521 a and the depressed sections 521 a appear respectively.

As described above, the uneven surface 521 in which the ridgelines 521 a extending in the vertical direction (a direction in which the axis C extends) and the depressed sections 521 b depressed in the arc shapes repeat alternately is formed on the inner wall surface of the inner space 520 of the main body 52. The tube 20 enters the main body 52 from the tube passing port 522, goes round circumferentially so as to be along the uneven surface 521, and again extends to the outside of the main body 52 from the tube passing port 522.

FIG. 18 illustrates a state in which the eccentric cam section 552 of the eccentric pin 52 presses the ring 53 toward a right side in this FIG. 18 (a side of circle R).

At this moment, in the tube 20, a left side part in FIG. 18 holds a state in which a section thereof is circular without being pressed by the ring 53, and a right side part in FIG. 18 is pressed against plural ridgelines by the ring 53.

At this moment, a portion of the tube 20 which portion is pressed against a ridgeline 521 a becomes an almost squeezed state as illustrated in part (A) of FIG. 20.

In addition, as illustrated in part (B) of FIG. 20, a portion of the tube 20 which portion faces a depressed section 521 b is also in a state of being almost squeezed, since even though the portion is not being pressed against a bottom most away from the axis C of the depressed section 521 b, both sides thereof are pressed against two ridgelines 521 a to be squeezed. As described, in the case of the present embodiment, since the pressing force concentrates into the portions of the ridgeline 521 b, the tube is squeezed even with a small force. In other words, even if the tube 20 is, for example, a PVC tube, it is possible to squeeze the tube with a force of a same extent as that for squeezing a silicon tube in the conventional structure. Specifically, since not an inner circumference surface which hardly deforms but an outer circumference surface which deforms relatively easily of the tube 20 is pressed against the ridgelines 521 a to be squeezed, it is possible to squeeze the tube 20 with a further smaller force.

As described above, in the present embodiment, the tube 20 is pressed against plural adjacent ridgelines 521 a of the uneven surface 521 to be squeezed by being sandwiched between each of the plural ridgelines 521 a across the tube 20, and with the rotation of the eccentric pin 55, a ridgeline contributing to the squeezing for the tube 20 is sequentially taken over by a ridgeline 521 a adjacent in the direction encircling the axis C illustrated in FIG. 15. With this, the fluid in the tube 20 is sent out.

Next, a pump main body to which the infusion pump cassette 50 of the second embodiment which has been explained above will be explained.

FIG. 21 is a perspective view of a pump main body when viewed from above.

This pump main body 60 includes a display panel 61 and plural operation buttons 62 on a left side of an upper surface thereof. In addition, the pump main body 60 includes an opening/closing lid 63 on a right side thereof. The opening/closing lid 63 includes an opening/closing lever 64. When the opening/closing lever 64 is rotated while a near side of the opening/closing 64 is being lifted, locking is released and thus the opening/closing lid 63 may be opened. As the tube 20 is illustrated in this FIG. 21, the infusion pump cassette 50 with the tube 20 attached is attached in an inside when the opening/closing lid 63 is opened.

FIG. 22 is a perspective view illustrating both of the pump main body in a state in which an opening/closing lid is opened and the infusion pump cassette. In here, FIG. 22 illustrates the infusion pump cassette 50 in a state in which a bottom surface to be attached to the pump main body 60 is oriented upward.

An attachment section 65 to receive an attachment of the infusion pump cassette 50 is provided in an inside of the pump main body 60 when the opening/closing lid 63 is opened. The infusion pump cassette 50 is attached to the attachment section 65 in an attitude in which the bottom surface thereof is oriented downward.

The attachment section 65 includes a rotation drive member 651 to transfer a rotation drive force to the infusion pump cassette 50, and four drive pins 651 a are arranged to stand up on the rotation drive member 651. When the infusion pump cassette 50 is attached to the attachment section 65 and the rotation drive member 651 is rotated by rotation of a motor, and then, the four drive pins 651 a respectively enter the four openings 553 a provided on the bottom surface of the infusion pump cassette 50, to rotate the eccentric pin 55 (see FIG. 15, FIG. 20, etc.) of the infusion pump cassette 50.

In addition, the attachment section 65 includes two depressed sections 652. The two arms 524 provided for rotation prevention in the main body 52 of the infusion pump cassette 50 respectively enter these depressed section 652, and play a role of preventing the main body 52 of the infusion pump cassette 50 from rotating. In addition, the attachment section 65 includes a tube receiving groove 653 in which the tube 20 connected to the infusion pump cassette 50 goes.

Further, a cassette holding section 67 which protrudes in a cylindrical shape is provided on the inside of the opening/closing lid 63. The cassette holding section 67 plays a role of receiving the cap 51 (see FIG. 15, FIG. 16, etc.) of the infusion pump cassette 50 in the inside thereof to hold an upper surface of the main body 52 from above when the infusion pump cassette 50 is attached to the attachment section 65 and the opening/closing lid 63 is closed. The opening/closing lid 63 includes a lock mechanism 69 to prevent the opening/closing lid 63 from opening so as to be locked when the opening/closing lid 63 is closed. Explanations of detailed configuration thereof are omitted. When a near side of the above-described opening/closing lever 64 is lifted up, the locking is released and the opening/closing lid 63 may be opened. In addition, a groove 66 having a wedge shape is provided on a bottom surface side of the pump main body 60. Usage of the groove 66 will be described later.

FIG. 23 is a view in which a casing of the pump main body is represented with two-dotted lines except for the opening/closing lid and an outline of an internal configuration thereof is illustrated.

A drive box 68 is arranged under the attachment section 65 (see FIG. 22) to which the infusion pump cassette 50 is attached. The motor, a gear array to transfer a rotation drive force of the motor and the like are housed in the drive box 68. When the motor of the drive box 68 rotates, the rotation drive member 651 illustrated in FIG. 22 rotates.

In addition, the pump main body 60 includes a battery 80. The battery 80 is for supplying electricity to sections requiring electricity such as the motor, the display panel 61 and the like. The pump main body 60 also includes, in addition to the elements illustrated in FIG. 23, a circuit board and other elements, and however, drawings and explanations thereof are omitted here.

FIG. 24 is a view illustrating behaviors when an infusion pump cassette is attached to an attachment section of the pump main body.

The drive box 68 includes a stand-up section 681 having a cylindrical shape, and the stand-up section 681 includes a vertical groove 682. When the motor in the box 68 rotates, the rotation thereof is transferred via the gear array and the stand-up section 681 also rotates about a rotation axis extending vertically. In addition, the rotation drive member 651 which directly transfers the rotation drive force to the infusion pump cassette 50 includes the drive pins 651 a on the upper surface thereof, and in addition, includes a hang-down section 651 b which hangs down downward and enters the vertical groove 682 of the stand-up section 681. A coil spring 654 is arranged between the stand-up section 681 and the rotation drive member 651. The coil spring 654 urges the rotation drive member 651 in a direction of lifting the rotation drive member 651 up. Incidentally, the rotation drive member 651 has a configuration that the rotation drive member 651 does not move more upward than a position illustrated in part (A) of FIG. 24 by a stopper which is not illustrated so as to maintain the state in which the hang-down section 651 b is entering the vertical groove 682.

Here, part (A) of FIG. 24 illustrates a state before the infusion pump cassette 50 is attached to the attachment section 65 (see FIG. 22) of the pump main body 60. At this moment, the rotation drive member 651 is in a state in which the rotation drive member 651 is pressed by the coil spring 654 and is lifted up.

Part (B) of FIG. 24 illustrates a state immediately after the infusion pump cassette 50 is attached to the attachment section 65 (see FIG. 22) of the pump main body 60. At this moment, the drive pins 651 a standing up on the upper surface of the rotation drive member 651 do not necessarily immediately enter the openings 553 a (see FIG. 17) provided on the bottom surface of the eccentric pin 55 of the infusion pump cassette 50, and when the drive pins 651 a are out of the openings 553 a, as illustrated in part (B) of FIG. 24, a state in which the drive pins 651 a are pressed by the lower surface of the eccentric pin 55 occurs. At this moment, a state in which the rotation drive member 651 is pressed from above and the coil spring 654 is compressed occurs.

When the motor in the drive box 68 starts to rotate, the stand-up section 681 and the rotation drive member 651 rotate, the drive pins 651 a enter the openings 553 a (see FIG. 17) on the bottom surface of the eccentric pin 55 at a timing when the drive pins 651 a face the openings 553 a, and thus, a state illustrated in part (C) of FIG. 24 occurs. After this, the rotation drive force of the motor is transferred to the eccentric pin 55 via the stand-up section 681 and the rotation drive member 651. The eccentric pin 55 rotates, and the fluid in the tube 20 is sent out in a manner as described above.

FIG. 25 is a view illustrating a bottom surface of the pump main body and a pump holder separately, and FIG. 26 is a view illustrating a state in which the pump main body is attached to the pump holder.

A pump holder 70 is a jig for attaching the pump main body 60 to a pole and the like. The pump holder 70 includes a projection 71 having a shape to couple with the groove 66 which is provided on the bottom surface of the pump main body 60 and has the wedge shape, and a table 72 on which the pump main body 60 is put, and the pump main body 60 is attached to the pump holder 70 in a state illustrated in FIG. 26. As described, the infusion pump including the infusion pump cassette 50 and the pump main body 60 according to the present embodiment have a configuration about which the usability of a user is taken into consideration. In addition, for the infusion pump cassette according to the present embodiments, it is possible to use a low cost tube such as a PVC tube without sacrificing size reduction and weight reduction, and has a configuration of contributing to decreasing the running cost.

In the foregoing, the first embodiment and the various modified examples thereof and the second embodiment have explained, and however, the inner wall surface of the main body member may have a simple shape of arc as the above-described first embodiment, or a shape of repeating unevenness as the second embodiment illustrated in FIG. 15, FIG. 16, or further, may have a different shape.

REFERENCE SIGNS LIST

-   10, 50, 101, 102, 103, 104 Infusion pump cassette -   11, 51 Cap -   12, 52 Main body -   13, 53 Ring -   14, 54 Holding plate -   15, 55 Eccentric pin -   16, 17 Stopper -   20 Tube -   30, 60 Pump main body -   31 Casing -   32 Motor -   33 Drive member -   112, 123 Slit -   120 Inner space -   121 Inner wall surface -   122 Lock claw -   122 a Operation section -   124 Fixing groove -   125 Opening -   126 Lock groove -   127 Flange -   128, 153 c Groove -   129, 334 c Projection -   151 Head section -   152 Eccentric cam section -   153 Disk section -   153 a Circumferential edge section -   153 b Bottom surface -   161, 312 Depressed section -   311 Attachment section -   331 Fixing plate -   332 Gear -   333 Drive shaft -   334 Head -   334 b Long opening -   335 Coil spring -   520 Inner space -   521 Uneven surface -   521 a Ridgeline -   521 b Depressed section -   522 Tube passing port -   523 Outer circumference surface -   524 Arm -   525 Slit -   526 Opening -   527 Fixing groove -   528 Guide groove -   551 Head section -   552 Eccentric cam section -   553 Disk section -   553 a Opening 

1. An infusion pump cassette comprising: a main body member that is defined by an inner wall surface which encircles an axis to spread, and that forms an inner space which receives a tube extending from an outside to arrange the tube along the inner wall surface and causes the tube to extend to the outside; a ring-shaped member that is installed in a position between the ring-shaped member and the inner wall surface across the tube in the inner space, and that is movable in a radius direction extending radially from the axis; and an eccentric member that is movable to an infusion position and a release position which are different in a direction of the axis, that has an eccentric shape in which, when being at the infusion position, the eccentric member presses the ring-shaped member from an inside of a ring thereof in a direction of the radius direction so as to press the tube against the inner wall surface by the ring-shaped member to squeeze the tube, and when being at the release position, the eccentric member loosens the pressing for the ring-shaped member or releases the ring-shaped member from the pressing so as to loosen the squeezing for the tube or release the tube from the squeezing, and that, when being at the infusion position, receives a rotation drive force from a motor to rotate about the axis so as to send a fluid in the tube out via the ring-shaped member.
 2. The infusion pump cassette according to claim 1, further comprising a fixing mechanism that fixes the eccentric member at the infusion position in a releasable manner.
 3. The infusion pump cassette according to claim 2, wherein the fixing mechanism includes a lock section that fixes the eccentric member being at the infusion position at the infusion position, and that, when a force of a predetermined value or more in a direction toward the release position is applied, releases the fixing so as to allow the eccentric member to go toward the release position.
 4. The infusion pump cassette according to claim 2, wherein the fixing mechanism includes a lock member that is movable between a lock position in which the lock member locks to the eccentric member being at the infusion position to cause the eccentric member to be immovable from the infusion position and a retraction position in which the lock member retracts from the lock position to make it possible for the eccentric member to move to the release position.
 5. The infusion pump cassette according to claim 1, wherein the inner wall surface of the main body member is an inner wall surface including an uneven surface in which plural ridgelines being arranged in a direction encircling the axis and in a same distance from the axis and plural depressed sections being depressed in directions more away from the axis than the ridgelines are alternately arranged.
 6. The infusion pump cassette according to claim 5, wherein the eccentric member causes, when being at the infusion position, the ring-shaped member to press the tube being received in the inner space against adjacent plural ridgelines of the uneven surface so as to sandwich the tube between the ring-shaped member and each of the plural ridgelines across the tube to squeeze the tube, and receives a rotation drive force from a motor to cause a ridgeline against which the tube is pressed to be sequentially taken over by a next ridgeline neighboring in the direction encircling the axis so as to send the fluid in the tube out.
 7. The infusion pump cassette according to claim 5, wherein the main body member includes plural slits which are formed separately with spaces in the direction encircling the axis and each of which penetrates from the inner wall surface to an external wall surface.
 8. An infusion pump comprising: an infusion pump cassette according to claim 1; and a pump main body that includes a motor therein, and receives an attachment of the infusion pump cassette to transfer a rotation drive force from the motor to the eccentric member being at the infusion position. 